Overtreatment with thyroid hormone (i.e., prescription at doses that are too high based on biochemical results) and its misuse (i.e., initiation for inappropriate indications) in older individuals may have adverse effects on bone health and lead to bone loss and fractures. This is critical as hip fracture mortality rates within the year of fracture reach up to 37% in older adults.19-22 Despite a higher death rate post hip fracture in men versus women23-25, most studies have focused on post-menopausal women26-31 and studies in men are sparse.32-34 The relationship between age and thyroid hormone replacement requirements is a heated debate, as the risk- benefit ratio of treatment for older adults is controversial. If providers assume that all individuals are treated similarly regardless f age, then older adults may be at risk for overtreatment, resulting in adverse effects on bone health. Furthermore, very little is known about factors that influence providers' decision-making regarding use of thyroid hormone replacement in older adults. The proposed project will address the following aims: Through secondary data analysis of the Veterans Health Administration National Patient Care Database, I will examine the rates of thyroid hormone overtreatment and misuse in older men (Specific Aim 1a) and determine the association between thyroid hormone overtreatment and misuse and skeletal risk in older men (Specific Aim 1b). Through national VA provider surveys, I will determine the influence of provider attitudes regarding overtreatment with and misuse of thyroid hormone replacement in older adults (Specific Aim 2). The overall goal of this application is to provide the groundwork for the candidate's growth and career development into an independent health services researcher with expertise in aging research in the field of thyroidology. With the proposed research project, the PI plans to develop a new niche in the field of thyroid disease management challenges in older adults, with an ultimate goal to develop tools to tailor treatment to this growing subpopulation. The following areas of career development for the proposed five-year award period have been identified: 1) to develop expertise in health services research in the field of aging, specifically addressing barriers to management of thyroid disorders in the aging population; 2) to develop expertise in study design and data collection methods, with a special focus on survey design; 3) to develop expertise in data analysis and interpretation, with a special focus on advanced biostatistical methods; 4) to develop expertise and scholarship in clinical and research aspects of gerontology and geriatrics, necessary to conduct high quality, clinically relevant aging research and 5) to develop into an independent investigator in the field of academic research in aging with a focus on thyroidology. A supportive institutional environment is also fundamental to the candidate's career development and growth. The University of Michigan, recognized for its excellence in health services research, endocrinology and geriatrics, provides an outstanding and supportive research environment.